Endoscopic cap electrode and method for using the same

ABSTRACT

An apparatus for treating tissue in a tissue treatment region. The apparatus can comprise an electrode ring having an interior perimeter and an electrode probe having a proximal end and a distal end. The distal end of the electrode probe can be structured to axially translate relative to the interior perimeter of the electrode ring. The electrode ring and the electrode probe can be operably structured to conduct current therebetween when at least one of the electrode ring and the electrode probe is energized by an energy source. Further, the energy source can be a Radio Frequency (RF) energy source, a pulsed energy source, an irreversible electroporation energy source, or a pulsed irreversible electroporation energy source. A current from the energy source can be selected to non-thermally ablate tissue in the tissue treatment region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 13/540,850, entitled ENDOSCOPIC CAP ELECTRODE AND METHOD FOR USING THE SAME, filed Jul. 3, 2012, issued Jul. 14, 2015, now U.S. Pat. No. 9,078,662 the entire disclosure of which is hereby incorporated by reference herein.

FIELD OF TECHNOLOGY

The present invention generally relates to surgical devices and methods.

BACKGROUND

Traditional, or open, surgical techniques may require a surgeon to make large incisions in a patient's body in order to access a tissue treatment region, or surgical site. In some instances, these large incisions may prolong the recovery time of and/or increase the scarring to the patient. As a result, minimally invasive surgical techniques are becoming more preferred among surgeons and patients owing to the reduced size of the incisions required for various procedures. In some circumstances, minimally invasive surgical techniques may reduce the possibility that the patient will suffer undesirable post-surgical conditions, such as scarring and/or infections, for example. Further, such minimally invasive techniques can allow the patient to recover more rapidly as compared to traditional surgical procedures.

Endoscopy is one minimally invasive surgical technique which allows a surgeon to view and evaluate a surgical site by inserting at least one cannula, or trocar, into the patient's body through a natural opening in the body and/or through a relatively small incision. In use, an endoscope can be inserted into, or through, the trocar so that the surgeon can observe the surgical site. In various embodiments, the endoscope may include a flexible or rigid shaft, a camera and/or other suitable optical device, and a handle portion. In at least one embodiment, the optical device can be located on a first, or distal, end of the shaft and the handle portion can be located on a second, or proximal, end of the shaft. In various embodiments, the endoscope may also be configured to assist a surgeon in taking biopsies, retrieving foreign objects, and introducing surgical instruments into the surgical site.

Laparoscopic surgery is another minimally invasive surgical technique where procedures in the abdominal or pelvic cavities can be performed through small incisions in the patient's body. A key element of laparoscopic surgery is the use of a laparoscope which typically includes a telescopic lens system that can be connected to a video camera. In various embodiments, a laparoscope can further include a fiber optic system connected to a halogen or xenon light source, for example, in order to illuminate the surgical site. In various laparoscopic, and/or endoscopic, surgical procedures, a body cavity of a patient, such as the abdominal cavity, for example, can be insufflated with carbon dioxide gas, for example, in order to create a temporary working space for the surgeon. In such procedures, a cavity wall can be elevated above the organs within the cavity by the carbon dioxide gas. Carbon dioxide gas is usually used for insufflation because it can be easily absorbed and removed by the body.

In at least one minimally invasive surgical procedure, an endoscope and/or laparoscope can be inserted through a natural opening of a patient to allow a surgeon to access a surgical site. Such procedures are generally referred to as Nature Orifice Transluminal Endoscopic Surgery or (NOTES)™ and can be utilized to treat tissue while reducing the number of incisions, and external scars, to a patient's body. In various NOTES™ procedures, for example, an endoscope can include at least one working channel defined therein, which can be used to allow the surgeon to insert a surgical instrument therethrough in order to access the surgical site.

Minimally invasive surgical procedures may employ electrical ablation therapy for the treatment of undesirable tissue such as diseased tissue, cancer, malignant and benign tumors, masses, lesions, and other abnormal tissue growths in a tissue treatment region. While conventional apparatuses, systems, and methods for the electrical ablation of undesirable tissue are effective, one drawback with conventional electrical ablation treatment is the resulting permanent damage that may occur to the healthy tissue surrounding the abnormal tissue due primarily to the detrimental thermal effects resulting from exposing the tissue to thermal energy generated by the electrical ablation device. This may be particularly true when exposing the tissue to electric potentials sufficient to cause cell necrosis using high temperature thermal therapies including focused ultrasound ablation, radiofrequency (RF) ablation, or interstitial laser coagulation. Other techniques for tissue ablation include chemical ablation, in which chemical agents are injected into the undesirable tissue to cause ablation as well as surgical excision, cryotherapy, radiation, photodynamic therapy, Moh's micrographic surgery, topical treatments with 5-fluorouracil, and/or laser ablation. Other drawbacks of conventional thermal, chemical, and other ablation therapy are cost, length of recovery, and the pain inflicted on the patient.

Conventional thermal, chemical, and other ablation techniques have been employed for the treatment of a variety of undesirable tissue. Thermal and chemical ablation techniques have been used for the treatment of varicose veins resulting from reflux disease of the greater saphenous vein (GSV), in which the varicose vein is stripped and then is exposed to either chemical or thermal ablation. Other techniques for the treatment of undesirable tissue are more radical. Prostate cancer, for example, may be removed using a prostatectomy, in which the entire or part of prostate gland and surrounding lymph nodes are surgically removed. Like most other forms of cancer, radiation therapy may be used in conjunction with or as an alternate method for the treatment of prostate cancer. Another thermal ablation technique for the treatment of prostate cancer is RF interstitial tumor ablation (RITA) via trans-rectal ultrasound guidance. While these conventional methods for the treatment of prostate cancer are effective, they are not preferred by many surgeons and may result in detrimental thermal effects to healthy tissue surrounding the prostate. Similar thermal ablation techniques may be used for the treatment of basal cell carcinoma (BCC) tissue, a slowly growing cutaneous malignancy derived from the rapidly proliferating basal layer of the epidermis. BCC tissue in tumors ranging in size from about 5 mm to about 40 mm may be thermally ablated with a pulsed carbon dioxide laser. Nevertheless, carbon dioxide laser ablation is a thermal treatment method and may cause permanent damage to healthy tissue surrounding the BCC tissue. Furthermore, this technique requires costly capital investment in carbon dioxide laser equipment.

Undesirable tissue growing inside a body lumen such as the esophagus, large bowel, or in cavities formed in solid tissue such as the breast, for example, can be difficult to destroy using conventional ablation techniques. Surgical removal of undesirable tissue, such as a malignant or benign tumor, from the breast is likely to leave a cavity. Surgical resection of residual intralumenal tissue may remove only a portion of the undesirable tissue cells within a certain margin of healthy tissue. Accordingly, some undesirable tissue is likely to remain within the wall of the cavity due to the limitation of conventional ablation instrument configurations, which may be effective for treating line-of-sight regions of tissue, but may be less effective for treating the residual undesirable tissue.

Accordingly, there remains a need for improved electrical ablation apparatuses, systems, and methods for the treatment of undesirable tissue found in diseased tissue, cancer, malignant and benign tumors, masses, lesions, and other abnormal tissue growths. There remains a need for minimally invasive treatment of undesirable tissue through the use of irreversible electroporation (IRE) ablation techniques without causing the detrimental thermal effects of conventional thermal ablation techniques.

The foregoing discussion is intended only to illustrate various aspects of the related art in the field of the invention at the time, and should not be taken as a disavowal of claim scope.

SUMMARY

An aspect of the present disclosure is directed to an apparatus for treating tissue in a tissue treatment region. The apparatus comprises an electrode ring comprising an interior perimeter and an electrode probe comprising a proximal end and a distal end. The distal end of the electrode probe is structured to axially translate relative to the interior perimeter of the electrode ring. The electrode ring and the electrode probe are operably structured to conduct current therebetween when at least one of the electrode ring and the electrode probe is energized by an energy source. Further, the energy source can be a Radio Frequency (RF) energy source, a pulsed energy source, an irreversible electroporation energy source, or a pulsed irreversible electroporation energy source.

An aspect of the present disclosure is related to an electrical ablation system comprising an energy source, a housing that comprises a working channel and a rim, and a probe moveably positioned through the working channel of the housing. The probe comprises a distal portion that is structured to move relative to the rim. Furthermore, the distal portion of the probe and the rim of the housing are operably structured to conduct current therebetween when at least one of the probe and the rim is energized by an energy source.

An aspect of the present disclosure is related to a method comprising the steps of obtaining an apparatus that comprises an electrode ring and an electrode probe. The electrode ring comprises an interior perimeter and a contact surface. The electrode probe comprises a proximal end and a distal end that is structured to axially translate relative to the interior perimeter of the electrode ring. The electrode ring and the electrode probe can be operably structured to conduct current therebetween when at least one of the electrode ring and the electrode probe is energized by an energy source. Further, the method can comprise the steps of positioning the contact surface of the electrode ring against tissue, moving the distal end of the electrode probe axially relative to the electrode ring, energizing at least one of the electrode ring and the electrode probe to conduct current therebetween, and/or applying a suctioning force to draw tissue into the electrode ring.

FIGURES

The novel features of the various described embodiments are set forth with particularity in the appended claims. The various embodiments, however, both as to organization and methods of operation, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings as follows.

FIG. 1 is a schematic of an electrical ablation system and a flexible endoscope according to various embodiments of the present disclosure;

FIG. 2 is a schematic illustrating one embodiment of the electrical ablation device of the electrical ablation system of FIG. 1 treating tissue in a tissue treatment region;

FIG. 3 is a schematic illustrating one embodiment of the electrical ablation device of FIG. 2 treating tissue in a tissue treatment region;

FIG. 4 is a perspective view of an electrical ablation device according to various embodiments of the present disclosure;

FIG. 5 is a perspective view of one embodiment of the electrical ablation device of FIG. 4 illustrating the cap of the device as transparent;

FIG. 6 is an elevational view of one embodiment of the electrical ablation device of FIG. 4;

FIG. 7 is an elevational view of one embodiment of the electrical ablation device of FIG. 4 with the cap and the attachment member removed therefrom;

FIG. 8 is an elevational view of one embodiment of the electrical ablation device of FIG. 4;

FIG. 9 is an elevational, cross-sectional view of one embodiment of the electrical ablation device of FIG. 4;

FIG. 10 is an elevational view of one embodiment of the electrical ablation device of FIG. 4 with the cap and the attachment member removed therefrom;

FIG. 11 is an elevational view of one embodiment of the electrode probe of the electrical ablation device of FIG. 4 having a needle tip and a temperature sensor;

FIG. 12 is a side view of an electrode probe having a blunt tip according to various embodiments of the present disclosure;

FIG. 13 is an elevational view of an electrode probe having a hooked tip according to various embodiments of the present disclosure;

FIG. 14 is an elevational view of an electrode probe having a pull cable according to various embodiments of the present disclosure;

FIG. 15 is a perspective, cross-sectional view of one embodiment of the attachment member of the electrical ablation device of FIG. 4;

FIG. 16 is an elevational, cross-sectional view illustrating engagement of the attachment member and the cap of one embodiment of the electrical ablation device of FIG. 4;

FIG. 17 is a perspective view of the cap of one embodiment of the electrical ablation device of FIG. 4;

FIG. 18 is an elevational view of the cap of one embodiment of the electrical ablation device of FIG. 4;

FIG. 19 is an elevational view of the cap of one embodiment of the electrical ablation device of FIG. 4;

FIG. 20 is a plan view of the cap of one embodiment of the electrical ablation device of FIG. 4;

FIG. 21 is a perspective view of the electrode ring of one embodiment of the electrical ablation device of FIG. 4 showing a plurality of temperature sensors around the perimeter;

FIG. 22 is a perspective view of the second conductor, second conductor extension, and electrode ring of one embodiment of the electrical ablation device of FIG. 4;

FIG. 23 is a schematic of one embodiment of the electrical ablation device of FIG. 4 illustrating a substantially conical necrotic zone; and

FIG. 24 is a schematic of one embodiment of the electrical ablation device of FIG. 4 illustrating a substantially conical necrotic zone.

DESCRIPTION

Various embodiments are directed to apparatuses, systems, and methods for the electrical ablation treatment of undesirable tissue such as diseased tissue, cancer, malignant and benign tumors, masses, lesions, and other abnormal tissue growths. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Further, the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment”, or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation.

It will be appreciated that the terms “proximal” and “distal” may be used throughout the specification with reference to a clinician manipulating one end of an instrument used to treat a patient. The term “proximal” refers to the portion of the instrument closest to the clinician and the term “distal” refers to the portion located furthest from the clinician. It will be further appreciated that for conciseness and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not intended to be limiting and absolute.

Electrical ablation devices in accordance with the described embodiments may comprise one or more electrodes configured to be positioned into or proximal to undesirable tissue in a tissue treatment region (e.g., target site, worksite) where there is evidence of abnormal tissue growth, for example. In general, the electrodes comprise an electrically conductive portion (e.g., medical grade stainless steel) and are configured to electrically couple to an energy source. Once the electrodes are positioned into or proximal to the undesirable tissue, an energizing potential is applied to the electrodes to create an electric field to which the undesirable tissue is exposed. The energizing potential (and the resulting electric field) may be characterized by multiple parameters such as frequency, amplitude, pulse width (duration of a pulse or pulse length), and/or polarity. Depending on the diagnostic or therapeutic treatment to be rendered, a particular electrode may be configured either as an anode (+) or a cathode (−) or may comprise a plurality of electrodes with at least one configured as an anode and at least one other configured as a cathode. Regardless of the initial polar configuration, the polarity of the electrodes may be reversed by reversing the polarity of the output of the energy source.

In various embodiments, a suitable energy source may comprise an electrical waveform generator, which may be configured to create an electric field that is suitable to create irreversible electroporation in undesirable tissue at various electric field amplitudes and durations. The energy source may be configured to deliver irreversible electroporation pulses in the form of direct-current (DC) and/or alternating-current (AC) voltage potentials (e.g., time-varying voltage potentials) to the electrodes. The irreversible electroporation pulses may be characterized by various parameters such as frequency, amplitude, pulse length, and/or polarity. The undesirable tissue may be ablated by exposure to the electric potential difference across the electrodes.

In one embodiment, the energy source may comprise a wireless transmitter to deliver energy to the electrodes using wireless energy transfer techniques via one or more remotely positioned antennas. Wireless energy transfer or wireless power transmission is the process of transmitting electrical energy from an energy source to an electrical load without interconnecting wires. An electrical transformer is the simplest instance of wireless energy transfer. The primary and secondary circuits of a transformer are not directly connected and the transfer of energy takes place by electromagnetic coupling through a process known as mutual induction. Power also may be transferred wirelessly using RF energy. Wireless power transfer technology using RF energy is produced by Powercast, Inc. and can achieve an output of 6 volts for a little over one meter. Other low-power wireless power technology has been proposed such as described in U.S. Pat. No. 6,967,462, the entire disclosure of which is incorporated by reference herein.

The apparatuses, systems, and methods in accordance with certain described embodiments may be configured for minimally invasive ablation treatment of undesirable tissue through the use of irreversible electroporation to be able to ablate undesirable tissue in a controlled and focused manner without inducing thermally damaging effects to the surrounding healthy tissue. The apparatuses, systems, and methods in accordance with the described embodiments may be configured to ablate undesirable tissue through the use of electroporation or electropermeabilization. More specifically, in various embodiments, the apparatuses, systems, and methods in accordance with the described embodiments may be configured to ablate undesirable tissue through the use of irreversible electroporation. Electroporation increases the permeabilization of a cell membrane by exposing the cell to electric pulses. The external electric field (electric potential/per unit length) to which the cell membrane is exposed to significantly increases the electrical conductivity and permeability of the plasma in the cell membrane. The primary parameter affecting the transmembrane potential is the potential difference across the cell membrane. Irreversible electroporation is the application of an electric field of a specific magnitude and duration to a cell membrane such that the permeabilization of the cell membrane cannot be reversed, leading to cell death without inducing a significant amount of heat in the cell membrane. The destabilizing potential forms pores in the cell membrane when the potential across the cell membrane exceeds its dielectric strength causing the cell to die under a process known as apoptosis and/or necrosis. The application of irreversible electroporation pulses to cells is an effective way to ablate large volumes of undesirable tissue without deleterious thermal effects to the surrounding healthy tissue associated with thermal-inducing ablation treatments. This is because irreversible electroporation destroys cells without heat and thus does not destroy the cellular support structure or regional vasculature. A destabilizing irreversible electroporation pulse, suitable to cause cell death without inducing a significant amount of thermal damage to the surrounding healthy tissue, may have amplitude in the range of about several hundred to about several thousand volts and is generally applied across biological membranes over a distance of about several millimeters, for example, for a relatively long duration. Thus, the undesirable tissue may be ablated in-vivo through the delivery of destabilizing electric fields by quickly creating cell necrosis.

The apparatuses, systems, and methods for electrical ablation therapy in accordance with the described embodiments may be adapted for use in minimally invasive surgical procedures to access the tissue treatment region in various anatomic locations such as the brain, lungs, breast, liver, gall bladder, pancreas, prostate gland, and various internal body lumen defined by the esophagus, stomach, intestine, colon, arteries, veins, anus, vagina, cervix, fallopian tubes, and the peritoneal cavity, for example, without limitation. Minimally invasive electrical ablation devices may be introduced to the tissue treatment region using a trocar inserted though a small opening formed in the patient's body or through a natural body orifice such as the mouth, anus, or vagina using translumenal access techniques known as Natural Orifice Translumenal Endoscopic Surgery (NOTES)™. Once the electrical ablation devices (e.g., electrodes) are located into or proximal to the undesirable tissue in the treatment region, electric field potentials can be applied to the undesirable tissue by the energy source. The electrical ablation devices can comprise portions that may be inserted into the tissue treatment region percutaneously (e.g., where access to inner organs or other tissue is done via needle-puncture of the skin). Other portions of the electrical ablation devices may be introduced into the tissue treatment region endoscopically (e.g., laparoscopically and/or thoracoscopically) through trocars or working channels of the endoscope, through small incisions, or transcutaneously (e.g., where electric pulses are delivered to the tissue treatment region through the skin).

FIG. 1 illustrates one embodiment of an electrical ablation system 10. The electrical ablation system 10 may be employed to ablate undesirable tissue such as diseased tissues, cancers, tumors, masses, lesions, abnormal tissue growths inside a patient using electrical energy. The electrical ablation system 10 may be used in conjunction with endoscopic, laparoscopic, thoracoscopic, open surgical procedures via small incisions or keyholes, percutaneous techniques, transcutaneous techniques, and/or external non-invasive techniques, or any combinations thereof without limitation. The electrical ablation system 10 may be configured to be positioned within a natural body orifice of the patient such as the mouth, anus, or vagina and advanced through internal body lumen or cavities such as the esophagus, colon, cervix, urethra, for example, to reach the tissue treatment region. The electrical ablation system 10 also may be configured to be positioned and passed through a small incision or keyhole formed through the skin or abdominal wall of the patient to reach the tissue treatment region using a trocar. The tissue treatment region may be located in the brain, lungs, breast, liver, gall bladder, pancreas, prostate gland, various internal body lumen defined by the esophagus, stomach, intestine, colon, arteries, veins, anus, vagina, cervix, fallopian tubes, and the peritoneal cavity, for example, without limitation. The electrical ablation system 10 can be configured to treat a number of lesions and ostepathologies comprising metastatic lesions, tumors, fractures, infected sites, and/or inflamed sites. Once positioned into or proximate the tissue treatment region, the electrical ablation system 10 can be actuated (e.g., energized) to ablate the undesirable tissue. In one embodiment, the electrical ablation system 10 may be configured to treat diseased tissue in the gastrointestinal (GI) tract, esophagus, lung, or stomach that may be accessed orally. In another embodiment, the electrical ablation system 10 may be adapted to treat undesirable tissue in the liver or other organs that may be accessible using translumenal access techniques such as, without limitation, NOTES™ techniques, where the electrical ablation devices may be initially introduced through a natural orifice such as the mouth, anus, or vagina and then advanced to the tissue treatment site by puncturing the walls of internal body lumen such as the stomach, intestines, colon, cervix. In various embodiments, the electrical ablation system 10 may be adapted to treat undesirable tissue in the brain, liver, breast, gall bladder, pancreas, or prostate gland, using one or more electrodes positioned percutaneously, transcutaneously, translumenally, minimally invasively, and/or through open surgical techniques, or any combination thereof.

In one embodiment, the electrical ablation system 10 may be employed in conjunction with a flexible endoscope 12, as well as a rigid endoscope, laparoscope, or thoracoscope, such as the GIF-H180 model available from Olympus Corporation. In one embodiment, the endoscope 12 may be introduced to the tissue treatment region trans-anally through the colon, trans-orally through the esophagus and stomach, trans-vaginally through the cervix, transcutaneously, or via an external incision or keyhole formed in the abdomen in conjunction with a trocar. The electrical ablation system 10 may be inserted and guided into or proximate the tissue treatment region using the endoscope 12.

In the embodiment illustrated in FIG. 1, the endoscope 12 comprises an endoscope handle 34 and an elongate relatively flexible shaft 32. The distal end of the flexible shaft 32 may comprise a light source and a viewing port. Optionally, the flexible shaft 32 may define one or more working channels for receiving various instruments, such as electrical ablation devices, for example, therethrough. Images within the field of view of the viewing port are received by an optical device, such as a camera comprising a charge coupled device (CCD) usually located within the endoscope 12, and are transmitted to a display monitor (not shown) outside the patient.

In one embodiment, the electrical ablation system 10 may comprise an electrical ablation device 20, a plurality of electrical conductors 18, a handpiece 16 comprising an activation switch 62, and an energy source 14, such as an electrical waveform generator, electrically coupled to the activation switch 62 and the electrical ablation device 20. The electrical ablation device 20 comprises a relatively flexible member or shaft 22 that may be introduced to the tissue treatment region using a variety of known techniques such as an open incision and a trocar, through one of more of the working channels of the endoscope 12, percutaneously, or transcutaneously, for example.

In one embodiment, one or more electrodes (e.g., needle electrodes, balloon electrodes), such as first and second electrodes 24 a,b, extend out from the distal end of the electrical ablation device 20. In one embodiment, the first electrode 24 a may be configured as the positive electrode and the second electrode 24 b may be configured as the negative electrode. The first electrode 24 a is electrically connected to a first electrical conductor 18 a, or similar electrically conductive lead or wire, which is coupled to the positive terminal of the energy source 14 through the activation switch 62. The second electrode 24 b is electrically connected to a second electrical conductor 18 b, or similar electrically conductive lead or wire, which is coupled to the negative terminal of the energy source 14 through the activation switch 62. The electrical conductors 18 a,b are electrically insulated from each other and surrounding structures, except for the electrical connections to the respective electrodes 24 a,b. In various embodiments, the electrical ablation device 20 may be configured to be introduced into or proximate the tissue treatment region using the endoscope 12 (laparoscope or thoracoscope), open surgical procedures, or external and non-invasive medical procedures. The electrodes 24 a,b may be referred to herein as endoscopic or laparoscopic electrodes, although variations thereof may be inserted transcutaneously or percutaneously. As discussed herein, either one or both electrodes 24 a,b may be adapted and configured to slideably move in and out of a cannula, lumen, or channel defined within the flexible shaft 22.

Once the electrodes 24 a,b are positioned at the desired location into or proximate the tissue treatment region, the electrodes 24 a,b may be connected to or disconnected from the energy source 14 by actuating or de-actuating the switch 62 on the handpiece 16. The switch 62 may be operated manually or may be mounted on a foot switch (not shown), for example. The electrodes 24 a,b deliver electric field pulses to the undesirable tissue. The electric field pulses may be characterized based on various parameters such as pulse shape, amplitude, frequency, and duration. The electric field pulses may be sufficient to induce irreversible electroporation in the undesirable tissue. The induced potential depends on a variety of conditions such as tissue type, cell size, and electrical pulse parameters. The primary electrical pulse parameter affecting the transmembrane potential for a specific tissue type is the amplitude of the electric field and pulse length that the tissue is exposed to.

In one embodiment, a protective sleeve or sheath 26 may be slideably disposed over the flexible shaft 22 and within a handle 28. In another embodiment, the sheath 26 may be slideably disposed within the flexible shaft 22 and the handle 28, without limitation. The sheath 26 is slideable and may be located over the electrodes 24 a,b to protect the trocar and prevent accidental piercing when the electrical ablation device 20 is advanced therethrough. Either one or both of the electrodes 24 a,b of the electrical ablation device 20 may be adapted and configured to slideably move in and out of a cannula, lumen, or channel formed within the flexible shaft 22. As described in greater detail herein, the second electrode 24 b may be fixed in place. The second electrode 24 b may provide a pivot about which the first electrode 24 a can be moved in an arc to other points in the tissue treatment region to treat larger portions of the diseased tissue that cannot be treated by fixing the electrodes 24 a,b in one location. In one embodiment, either one or both of the electrodes 24 a,b may be adapted and configured to slideably move in and out of a working channel formed within a flexible shaft 32 of the flexible endoscope 12 or may be located independently of the flexible endoscope 12.

In one embodiment, the first and second electrical conductors 18 a,b may be provided through the handle 28. In the illustrated embodiment, the first electrode 24 a can be slideably moved in and out of the distal end of the flexible shaft 22 using a slide member 30 to retract and/or advance the first electrode 24 a. In various embodiments either or both electrodes 24 a,b may be coupled to the slide member 30, or additional slide members, to advance and retract the electrodes 24 a,b, e.g., position the electrodes 24 a,b. In the illustrated embodiment, the first electrical conductor 18 a coupled to the first electrode 24 a is coupled to the slide member 30. In this manner, the first electrode 24 a, which is slideably movable within the cannula, lumen, or channel defined by the flexible shaft 22, can advanced and retracted with the slide member 30.

In various other embodiments, transducers or sensors 29 may be located in the handle 28 of the electrical ablation device 20 to sense the force with which the electrodes 24 a,b penetrate the tissue in the tissue treatment zone. This feedback information may be useful to determine whether either one or both of the electrodes 24 a,b have been properly inserted in the tissue treatment region. As is particularly well known, cancerous tumor tissue tends to be denser than healthy tissue and thus greater force is required to insert the electrodes 24 a,b therein. The transducers or sensors 29 can provide feedback to the operator, surgeon, or clinician to physically sense when the electrodes 24 a,b are placed within the cancerous tumor. The feedback information provided by the transducers or sensors 29 may be processed and displayed by circuits located either internally or externally to the energy source 14. The sensor 29 readings may be employed to determine whether the electrodes 24 a,b have been properly located within the cancerous tumor thereby assuring that a suitable margin of error has been achieved in locating the electrodes 24 a,b.

In one embodiment, the input to the energy source 14 may be connected to a commercial power supply by way of a plug (not shown). The output of the energy source 14 is coupled to the electrodes 24 a,b, which may be energized using the activation switch 62 on the handpiece 16, or in one embodiment, an activation switch mounted on a foot activated pedal (not shown). The energy source 14 may be configured to produce electrical energy suitable for electrical ablation, as described in more detail herein.

In one embodiment, the electrodes 24 a,b are adapted and configured to electrically couple to the energy source 14 (e.g., generator, waveform generator). Once electrical energy is coupled to the electrodes 24 a,b, an electric field is formed at a distal end of the electrodes 24 a,b. The energy source 14 may be configured to generate electric pulses at a predetermined frequency, amplitude, pulse length, and/or polarity that are suitable to induce irreversible electroporation to ablate substantial volumes of undesirable tissue in the treatment region. For example, the energy source 14 may be configured to deliver DC electric pulses having a predetermined frequency, amplitude, pulse length, and/or polarity suitable to induce irreversible electroporation to ablate substantial volumes of undesirable tissue in the treatment region. The DC pulses may be positive or negative relative to a particular reference polarity. The polarity of the DC pulses may be reversed or inverted from positive-to-negative or negative-to-positive a predetermined number of times to induce irreversible electroporation to ablate substantial volumes of undesirable tissue in the treatment region.

In one embodiment, a timing circuit may be coupled to the output of the energy source 14 to generate electric pulses. The timing circuit may comprise one or more suitable switching elements to produce the electric pulses. For example, the energy source 14 may produce a series of n electric pulses (where n is any positive integer) of sufficient amplitude and duration to induce irreversible electroporation suitable for tissue ablation when the n electric pulses are applied to the electrodes 24 a,b. In one embodiment, the electric pulses may have a fixed or variable pulse length, amplitude, and/or frequency.

The electrical ablation device 20 may be operated either in bipolar or monopolar mode. In bipolar mode, the first electrode 24 a is electrically connected to a first polarity and the second electrode 24 b is electrically connected to the opposite polarity. For example, in monopolar mode, the first electrode 24 a is coupled to a prescribed voltage and the second electrode 24 b is set to ground. In the illustrated embodiment, the energy source 14 may be configured to operate in either the bipolar or monopolar modes with the electrical ablation system 10. In bipolar mode, the first electrode 24 a is electrically connected to a prescribed voltage of one polarity and the second electrode 24 b is electrically connected to a prescribed voltage of the opposite polarity. When more than two electrodes are used, the polarity of the electrodes may be alternated so that any two adjacent electrodes may have either the same or opposite polarities, for example.

In one embodiment, the energy source 14 may be configured to produce RF waveforms at predetermined frequencies, amplitudes, pulse widths or durations, and/or polarities suitable for electrical ablation of cells in the tissue treatment region. One example of a suitable RF energy source is a commercially available conventional, bipolar/monopolar electrosurgical RF generator such as Model Number ICC 350, available from Erbe, GmbH.

In one embodiment, the energy source 14 may be configured to produce destabilizing electrical potentials (e.g., fields) suitable to induce irreversible electroporation. The destabilizing electrical potentials may be in the form of bipolar/monopolar DC electric pulses suitable for inducing irreversible electroporation to ablate tissue undesirable tissue with the electrical ablation device 20. A commercially available energy source suitable for generating irreversible electroporation electric filed pulses in bipolar or monopolar mode is a pulsed DC generator such as Model Number ECM 830, available from BTX Molecular Delivery Systems. In bipolar mode, the first electrode 24 a may be electrically coupled to a first polarity and the second electrode 24 b may be electrically coupled to a second (e.g., opposite) polarity of the energy source 14. Bipolar/monopolar DC electric pulses may be produced at a variety of frequencies, amplitudes, pulse lengths, and/or polarities. Unlike RF ablation systems, however, which require high power and energy levels delivered into the tissue to heat and thermally destroy the tissue, irreversible electroporation requires very little energy input into the tissue to kill the undesirable tissue without the detrimental thermal effects because with irreversible electroporation the cells are destroyed by electric field potentials rather than heat.

In one embodiment, the energy source 14 may be coupled to the first and second electrodes 24 a,b by either a wired or a wireless connection. In a wired connection, the energy source 14 is coupled to the electrodes 24 a,b by way of the electrical conductors 18 a,b, as shown. In a wireless connection, the electrical conductors 18 a,b may be replaced with a first antenna (not shown) coupled the energy source 14 and a second antenna (not shown) coupled to the electrodes 24 a,b, wherein the second antenna is remotely located from the first antenna. In one embodiment, the energy source may comprise a wireless transmitter to deliver energy to the electrodes using wireless energy transfer techniques via one or more remotely positioned antennas.

In at least one embodiment, the energy source 14 can be configured to produce DC electric pulses at frequencies in the range of approximately 1 Hz to approximately 10000 Hz, amplitudes in the range of approximately ±100 to approximately ±8000 VDC, and pulse lengths (e.g., pulse width, pulse duration) in the range of approximately 1 μs to approximately 100 ms. In at least one embodiment, the energy source can be configured to produce biphasic waveforms and/or monophasic waveforms that alternate around approximately 0V. In various embodiments, for example, the polarity of the electric potentials coupled to the electrodes 24 a,b can be reversed during the electrical ablation therapy. For example, initially, the DC electric pulses can have a positive polarity and an amplitude in the range of approximately +100 to approximately +3000 VDC. Subsequently, the polarity of the DC electric pulses can be reversed such that the amplitude is in the range of approximately −100 to approximately −3000 VDC. In another embodiment, the DC electric pulses can have an initial positive polarity and amplitude in the range of approximately +100 to +6000 VDC and a subsequently reversed polarity and amplitude in the range of approximately −100 to approximately −6000 VDC.

In at least one embodiment, the undesirable cells in the tissue treatment region can be electrically ablated with DC pulses suitable to induce irreversible electroporation at frequencies of approximately 10 Hz to approximately 100 Hz, amplitudes in the range of approximately +700 to approximately +1500 VDC, and pulse lengths of approximately 10 μs to approximately 50 μs. In another embodiment, the abnormal cells in the tissue treatment region can be electrically ablated with an electrical waveform having an amplitude of approximately +500 VDC and pulse duration of approximately 20 ms delivered at a pulse period T or repetition rate, frequency f=1/T, of approximately 10 Hz. In another embodiment, the undesirable cells in the tissue treatment region can be electrically ablated with DC pulses suitable to induce irreversible electroporation at frequencies of approximately 200 Hz, amplitudes in the range of approximately +3000 VDC, and pulse lengths of approximately 10 ms. It has been determined that an electric field strength of 1,000V/cm can be suitable for destroying living tissue by inducing irreversible electroporation by DC electric pulses.

In various embodiments, the energy source 14 can be configured to produce AC electric pulses at frequencies in the range of approximately 1 Hz to approximately 10000 Hz, amplitudes in the range of approximately ±8000 to approximately ±8000 VAC, and pulse lengths (e.g., pulse width, pulse duration) in the range of approximately 1 μs to approximately 100 ms. In one embodiment, the undesirable cells in the tissue treatment region can be electrically ablated with AC pulses suitable to induce irreversible electroporation at pulse frequencies of approximately 4 Hz, amplitudes of approximately ±6000 VAC, and pulse lengths of approximately 20 ms. It has been determined that an electric field strength of 1,500V/cm can be suitable for destroying living tissue by inducing irreversible electroporation by AC electric pulses.

Various electrical ablation devices are disclosed in commonly-owned U.S. patent application Ser. No. 11/897,676 titled “ELECTRICAL ABLATION SURGICAL INSTRUMENTS,” filed Aug. 31, 2007, now U.S. Patent Application Publication No. 2009/0062788, the entire disclosure of which is incorporated herein by reference in its entirety. Various other devices are disclosed in commonly-owned U.S. patent application Ser. No. 12/352,375, titled “ELECTRICAL ABLATION DEVICES”, filed on Jan. 12, 2009, now U.S. Patent Application Publication No. 2010/0179530 the entire disclosure of which is incorporated herein by reference in its entirety.

FIG. 2 illustrates one embodiment of the electrical ablation system 10 shown in FIG. 1 in use to treat undesirable tissue 48 located in the liver 50. The undesirable tissue 48 may be representative of a variety of diseased tissues, cancers, tumors, masses, lesions, abnormal tissue growths, for example. In use, the electrical ablation device 20 may be introduced into or proximate the tissue treatment region through a port 52 of a trocar 54. The trocar 54 is introduced into the patient via a small incision 59 formed in the skin 56. The endoscope 12 may be introduced into the patient trans-anally through the colon, trans-vaginally, trans-orally down the esophagus and through the stomach using translumenal techniques, or through a small incision or keyhole formed through the patient's abdominal wall (e.g., the peritoneal wall). The endoscope 12 may be employed to guide and locate the distal end of the electrical ablation device 20 into or proximate the undesirable tissue 48. Prior to introducing the flexible shaft 22 through the trocar 54, the sheath 26 is slid over the flexible shaft 22 in a direction toward the distal end thereof to cover the electrodes 24 a,b until the distal end of the electrical ablation device 20 reaches the undesirable tissue 48.

Once the electrical ablation device 20 has been suitably introduced into or proximate the undesirable tissue 48, the sheath 26 is retracted to expose the electrodes 24 a,b to treat the undesirable tissue 48. To ablate the undesirable tissue 48, the operator initially may locate the first electrode 24 a at a first position 58 a and the second electrode 24 b at a second position 60 using endoscopic visualization and maintaining the undesirable tissue 48 within the field of view of the flexible endoscope 12. The first position 58 a may be near a perimeter edge of the undesirable tissue 48. Once the electrodes 24 a,b are located into or proximate the undesirable tissue 48, the electrodes 24 a,b are energized with irreversible electroporation pulses to create a first necrotic zone 65 a. For example, once the first and second electrodes 24 a,b are located in the desired positions 60 and 58 a, the undesirable tissue 48 may be exposed to an electric field generated by energizing the first and second electrodes 24 a,b with the energy source 14. The electric field may have a magnitude, frequency, and pulse length suitable to induce irreversible electroporation in the undesirable tissue 48 within the first necrotic zone 65 a. The size of the necrotic zone is substantially dependent on the size and separation of the electrodes 24 a,b, as previously discussed. The treatment time is defined as the time that the electrodes 24 a,b are activated or energized to generate the electric pulses suitable for inducing irreversible electroporation in the undesirable tissue 48.

This procedure may be repeated to destroy relatively larger portions of the undesirable tissue 48. The position 60 may be taken as a pivot point about which the first electrode 24 a may be rotated in an arc of radius “r,” the distance between the first and second electrodes 24 a,b. Prior to rotating about the second electrode 24 b, the first electrode 24 a is retracted by pulling on the slide member 30 in a direction toward the proximal end and rotating the electrical ablation device 20 about the pivot point formed at position 60 by the second electrode 24 b. Once the first electrode 24 a is rotated to a second position 58 b, it is advanced to engage the undesirable tissue 48 at point 58 b by pushing on the slide member 30 in a direction towards the distal end. A second necrotic zone 65 b is formed upon energizing the first and second electrodes 24 a,b. A third necrotic zone 65 c is formed by retracting the first electrode 24 a, pivoting about pivot point 60 and rotating the first electrode 24 a to a new location in third position 58 c, advancing the first electrode 24 a into the undesirable tissue 48 and energizing the first and second electrodes 24 a,b. This process may be repeated as often as necessary to create any number of necrotic zones 65 p, where p is any positive integer, within multiple circular areas of radius “r,” for example, that is suitable to ablate the entire undesirable tissue 48 region. At anytime, the surgeon or clinician can reposition the first and second electrodes 24 a,b and begin the process anew. Those skilled in the art will appreciate that similar techniques may be employed to ablate any other undesirable tissues that may be accessible trans-anally through the colon, and/or orally through the esophagus and the stomach using translumenal access techniques. Therefore, the embodiments are not limited in this context.

FIG. 3 illustrates a detailed view of one embodiment of the electrical ablation system 10 shown in FIG. 2 in use to treat undesirable tissue 48 located in the liver 50. The first and second electrodes 24 a,b are embedded into or proximate the undesirable tissue 48 on the liver 50. The first and second electrodes 24 a,b are energized to deliver one or more electrical pulses of amplitude and length sufficient to induce irreversible electroporation in the undesirable tissue 48 and create the first necrotic zone 65 a. Additional electric pulses may be applied to the tissue immediately surrounding the respective electrodes 24 a,b to form second, thermal, necrotic zones 63 a,b near the electrode-tissue-interface. The duration of an irreversible electroporation energy pulse determines whether the temperature of the tissue 63 a,b immediately surrounding the respective electrodes 24 a,b raises to a level sufficient to create thermal necrosis. As previously discussed, varying the electrode 24 a,b size and spacing can control the size and shape of irreversible electroporation induced necrotic zone 65 a. Electric pulse amplitude and length can be varied to control the size and shape of the thermally induced necrotic zones near the tissue-electrode-interface.

Referring now to FIGS. 4-22, in various embodiments, an electrical ablation device 120 can comprise a first electrode 124 and a second electrode 125. In various embodiments the first electrode 124 can comprise of an electrode probe, for example, and the second electrode 125 can comprise of an electrode ring, for example. As described in greater detail herein, the electrode probe 124 can be configured to move axially relative to the electrode ring 125, for example. In various embodiments, the electrical ablation device 120 can comprise a plurality of electrode probes 124 and/or a plurality of electrode rings 125. Similar to the electrodes 24 a and 24 b, described in greater detail herein, the first electrode 124 and the second electrode 125 can be structured to conduct current therebetween when at least one of the electrodes 124, 125 is energized by an energy source 14 (FIG. 1). Furthermore, the energy source 14 (FIG. 1) that is coupled to at least one of the first and/or second electrodes 124, 125 can comprise a radio frequency (RF) energy source, a pulsed energy source, an irreversible electroporation energy source and/or a pulsed electroporation energy source, for example. Furthermore, as described in greater detail herein, the pulse length, amplitude, and/or frequency can be selected to non-thermally ablate tissue. Also, the energy source 14 (FIG. 1) can be configured to produce direct and/or alternating current resulting in biphasic and/or monophasic waveforms, as described in greater detail here.

In various embodiments the electrical ablation device 120 can comprise a flexible shaft 122, an attachment member 160 and/or a cap 140. As described in greater detail herein, the attachment number 160 can be coupled to the flexible shaft 122 at or near the distal end 192 thereof. Furthermore, in some embodiments, the cap 140 can releasably engage the attachment member 160. In various embodiments, a bore 190 may extend through the attachment portion 160 and/or through the cap 140 and at least a portion of the flexible shaft 122 can be positioned in the bore 190, for example. In some embodiments, at least a portion of the electrode probe 124 can be axially positioned through at least a portion of the flexible shaft 122, the attachment member 160 and/or the cap 140, for example. Furthermore, the electrode probe 124 can comprise a first conductor 118 extending therefrom, for example. In various embodiments, at least a portion of the electrode probe 124 and/or first conductor 118 can be configured to move within at least one of the flexible shaft 122, the attachment member 160 and/or the cap 140, for example. In various embodiments, the first conductor 118 can be configured to slide, translate, rotate, or a combination thereof within the flexible shaft 122. For example, the first conductor 118 can be configured to translate within the flexible shaft 122, the attachment member 160 and the cap 140. Similar to the slide member 30 (FIG. 1) described in greater detail here, a slide member can operably move the electrode probe 124. In various embodiments, the slide member can be coupled to the first conductor 118. In such embodiments, the electrode probe 124 can be slideably moved in and out of the distal end of the flexible shaft 122 using the slide member to retract and/or advance the first conductor 118, for example.

In various embodiments, the electrical ablation device 120 can comprise a plurality of electrode probes 124. The electrode probes can be configured to move within the flexible shaft 122, attachment member 160 and/or the cap 140, for example. The electrode probes can move together and/or independently, for example. Furthermore, each electrode probe can comprise a conductor, for example. Alternatively or additionally, at least two electrode probes can extend from a single conductor, for example.

Referring now primarily to the embodiment illustrated in FIG. 11, the first electrode or electrode probe 124 can comprise a distal end 170. In various embodiments, a needle tip 172 can be positioned at or near the distal end 170 of the electrode probe 124. In various embodiments, the electrode probe 124 can also comprise at least one temperature sensor 174. The temperature sensor can be positioned at or near the distal end 170 of the electrode probe 124, for example. In various embodiments, the temperature sensor 174 can measure the temperature of tissue 63 a (FIG. 3) immediately surrounding the electrode probe 124, for example. The sensor 174 can communicate the measurement to transducers and/or circuits located either internally or externally to the flexible endoscope 12 and/or the energy source 14 (FIG. 1). The sensor 174 can provide feedback to the operator, surgeon, or clinician such that the operator, surgeon, or clinician can adjust the power level of the energy source 14 (FIG. 1) to prevent thermal ablation of the tissue 63 a immediately surrounding the electrode probe 124. In other embodiments, the sensor 174 can provide feedback to the operator, surgeon, or clinician such that the operator, surgeon or clinician can adjust the power level to thermally ablate tissue 63 a immediately surrounding the electrode probe 124. As described in greater detail herein, the electrode ring 125 can also comprise at least one temperature sensor 158 such that a temperature gradient across the tissue treatment region can be determined and communicated to the operator, surgeon or clinician.

Referring now to the embodiment illustrated in FIG. 12, in various embodiments a second electrode probe 224 can comprise a substantially flat or blunt distal end 270. In other embodiments, referring now to the embodiment illustrated in FIG. 13, an electrode probe 324 can comprise a hooked tip 326, for example. In various embodiments, the hooked tip 326 can be inserted into tissue in a tissue treatment region and then retracted such that the tip 326 pulls and/or draws the tissue into the cap 140. Similar to the suction force described in greater detail herein, the amount of tissue drawn into the cap 140 by the hooked tip 326 can affect the necrotic zone treated by the electrical ablation device 120. In other embodiments, referring now to the embodiment illustrated in FIG. 14, the distal end 470 of the electrode probe 424 can comprise a pull string 474, for example. In various embodiments, the pull string 474 can be positioned at and/or near a needle tip 472 at the distal end 470 of the electrode probe 424, for example. The draw pull 474 can be looped around the electrode probe 424. In various embodiments, the operator, surgeon or clinician can control the position of the distal end 470 of the electrode probe 424 by manipulating the draw string 474 such that the distal end 470 of the electrode probe 424 moves, pivots, and/or bends relative to electrode ring 125 (FIG. 7), for example.

Referring now primarily to the embodiment illustrated in FIGS. 5 and 9, the electrode probe 124 can be positioned relative to the flexible shaft 122. In various embodiments, the flexible shaft 122 can comprise an elastic and/or resilient material such that the flexible shaft 122 can bend, twist, torque, and/or be otherwise manipulated by the operator, surgeon, or clinician during use, similar to flexible shaft 22 (FIGS. 1 and 2) described in greater detail herein. In some embodiments, at least a portion of the electrode probe 124 can be positioned within a bore 136 that extends through the flexible shaft 122 from a proximal end 191 to a distal end 192 thereof. In various embodiments, the flexible shaft 122 can comprise a top surface 137 at the distal end 192 having an opening 138 therein. The bore 136 can extend through the flexible shaft 122 to the opening 138 in the top surface 137, for example. As described in greater detail herein, the first conductor 118 can extend from the first electrode 124. In various embodiments, the first conductor 118 of the electrode probe 124 can extend through the bore 136. In various embodiments, an inner surface of the bore 136 can comprise an insulated material such that the electrode probe 124 and/or first conductor 118 is electrically insulated from the flexible shaft 122 and/or the electrical ablation device 120, for example. For example, an insulating coating can cover the inner surface of the bore 136 along the length of the flexible shaft 122. Additionally or alternatively, the first conductor 118 can comprise an insulated material such that the electrode probe 124 and/or first conductor 118 is electrically insulated from the flexible shaft 122 and/or the electrical ablation device 120, for example. For example, an insulating coating can cover the outer surface of the second conductor 118 along the length thereof.

In various embodiments, the electrical ablation device 120 can comprise an attachment member 160. Referring primarily to FIG. 9, the attachment member 160 can be coupled to the flexible shaft 122. In various embodiments, the attachment member 160 can be fixedly attached to the flexible shaft 122. The attachment member 160 can be attached to the flexible shaft 122 by an adhesive and/or by threads (not shown) in the flexible shaft 122 and attachment member 160, for example. In some embodiments, the attachment member 160 can be an integral component of the flexible shaft 122, for example, such that the flexible shaft 122 and attachment member 160 comprise a single, integrated piece.

Referring now to the embodiment illustrated in FIGS. 15 and 16, the attachment member 160 can comprise a body 162 and an inner surface 163. In various embodiments, the attachment member 160 can also comprise an attachment portion 164. The attachment portion 164 can comprise at least one connective ridge 166, for example. In various embodiments, the attachment portion 164 can comprise a plurality of connective ridges 166. The connective ridge 166 can extend from the body 162 of the attachment member 160 and into the bore 190 defined by the body 162 of the attachment member 160. In various embodiments, the connective ridge 166 can comprise an annular or semi-annular projection from the inner surface 163 of the attachment member 160. In various embodiments, the connective ridge 163 can comprise a plurality of projections from the inner surface 163 of the attachment member. In such embodiments, gaps (not shown) can be positioned intermediate the projections, for example.

In some embodiments, the connective ridge 166 can comprise a flat edge 165 and/or a contoured edge 167. As described in greater detail herein, the flat edge 165 and/or contoured edge 167 of the connective ridge 166 can be configured to engage an element on the cap 140 such that the connective member 160 is attached to the cap 140. In some embodiments, the attachment member 160 can be fixedly attached the cap 140. In other embodiment, the attachment member 160 can be removably attached to the cap 140 such as, for example, by a detent assembly, a plurality of spring-loaded pins, a resilient projection extending from the body 162 of the attachment member 160 and/or threads, for example, on the inner surface 163 of the body 162 that are configured to threadably engage corresponding threads in the cap 140. In various embodiments, the attachment member 160 can also comprise a channel 168, which is configured to receive at least a portion of the second conductor 119 and/or second conductor extension 180, as described in greater detail herein.

Referring now to FIGS. 16-20, the cap 140 of the electrical ablation device 120 can comprise a body portion 142. In various embodiments, the body portion 142 can comprise a substantially cylindrical shape. In other embodiments, the body 142 can comprise a circular, elliptical and/or polygonal cross-section, for example. Furthermore, in some embodiments, the cap 140 may not form a completely closed loop or shape, but can comprise a gap, for example. In various embodiments, the cap 140 can comprise a rim 144. In some embodiments, the rim 144 can be positioned at the distal end of the body 142 of the cap 140.

In various embodiments, referring still to FIGS. 16-20, an attachment portion 147 can be positioned at a proximal end or portion of the cap 140. The attachment portion 147 can releasably secure the cap 140 to the attachment portion 164 of the attachment member 160, as described in greater detail herein. In various embodiments, the attachment portion 147 of the cap 140 can fit within the attachment member 160, for example. In other embodiments, the attachment portion 164 of the attachment member 160 can fit within the attachment portion 147 of the cap 140, for example. In various embodiments, the attachment portion 147 can comprise a flange 148, for example. In some embodiments, the flange 148 can comprise a smaller diameter than the diameter of the body portion 142 of the cap 140. The flange 148 can be configured to fit within the attachment portion 164 of the attachment member 160. In some embodiments, the flange 147 can comprise at least one depression 149 that is configured to engage a connective ridge 166 in the attachment portion 164 of the attachment member 160, for example. The depression 149 in the flange 147 can receive the connective ridge 166, for example. In some embodiments, the connective ridge 166 can engage the depression 149 of the flange 148 of the attachment portion 160 by a snap-fit engagement. In various embodiments, the attachment portion 147 can comprise a plurality of depressions 149. For example, the attachment portion 147 can comprise the same number of depressions as the attachment member 160 comprises number of connective ridges 166 such that each connective ridge 166 is configured to engage one depression 149 in the attachment portion 147 of the cap 140.

Referring now primarily to the embodiment illustrated in FIGS. 18 and 19, the cap 140 can comprise a rim 144. In various embodiments, portions of the rim 144 can comprise a curved, angled, and/or flat surface(s), for example. In various embodiments, the rim 144 can slant across the diameter of the cap 140, for example, such that the rim 144 slants relative to a proximal portion of the cap 140. For example, the rim 144 can be angularly positioned relative to flange 148 and/or depression 149 in the attachment portion 147 of the cap 140. Referring primarily to FIG. 20, in various embodiments, the rim 144 of the cap 140 can comprise a step or contour 145. In various embodiments, as described in greater detail herein, the contour 145 can be configured to receive at least a portion of electrode ring 125, for example. In some embodiments, the contour 145 can match or substantially match the bottom surface of the electrode ring 125, as described in greater detail herein. In some embodiments, the cap 140 can also comprise a channel 143 that is configured to receive the second conductor 119 and/or the second conductor extension 180, for example. Furthermore, the cap 140 can comprise an inner surface 146 that defines the bore 190 through the cap 140 and/or through the attachment portion 160, for example.

Referring now to the embodiment illustrated in FIG. 16, the cap 140 can be configured to engage the attachment portion 160. In various embodiments, the attachment portion 164 of the attachment member 160 can engage the attachment portion 147 of the cap 140, for example. As shown in FIG. 16, the connective ridge 166 of the attachment portion 164 of the attachment member 160 can engage the depression 149 in the flange 148 of the attachment portion 147 of the cap 140. In various embodiments, the outer surface of the flange 148 can be configured to abut the inner surface 163 of the attachment member 160, for example. Furthermore, when the attachment member 160 is removably attached to the cap 140, the channel 158 in the attachment member 160 can be aligned with or substantially aligned with the channel 143 in the cap 140. As described in greater detail herein, the channels 168 and 143 can be configured to receive at least a portion of the second conductor 119 and/or second conductor extension 180, for example.

In various embodiments, referring now to the embodiment illustrated in FIG. 21, the electrode ring 125 of the electrical ablation device 120 can comprise a perimeter 150. The perimeter 150 can further comprise an interior perimeter 151, for example. Furthermore, the electrode ring 125 can comprise a tissue contacting surface 152. In various embodiments, as described in greater detail herein, the electrode ring 125 can be positioned adjacent to, against, and/or abutting tissue in a tissue treatment region. In various embodiments, the tissue contacting surface 152 of the electrode ring 125 can be configured to contact the tissue. In some embodiments, the electrode ring 125 can also comprise a groove 156. As described in greater detail herein, the groove 156 can be configured to receive the second conductor extension 180, for example.

In various embodiments, the electrode ring 125 can comprise a substantially or partially annular perimeter 150. In other embodiments, the electrode ring 125 can comprise a substantially circular, elliptical and/or polygonal perimeter 150. For example, the electrode ring 125 can comprise at least one arc, contour and/or corner around the perimeter 150 thereof. In various embodiments, the perimeter 150 of the electrode ring 125 can comprise a completely or substantially closed loop. In other embodiments, the perimeter 150 of the electrode ring 125 can comprise at least a first and second end and a gap or space positioned between the first and second end. In some embodiments, the electrode ring 125 can comprise a plurality of gaps. Furthermore, in various embodiments, a gap in the perimeter 150 of the electrode ring 125 can comprise a narrow width. In other embodiments, the gap can comprise a wider width. The electrode ring 125 can comprise a semi-circular shape and can, for example, comprises a narrow gap therein. In other embodiments, the electrode ring 125 can comprise a crescent moon shape, for example, such that the electrode ring 125 comprises a wider gap therein.

Referring now to the embodiment illustrated in FIG. 22, the electrode ring 125 can also comprise a bottom surface 154. In various embodiments, the bottom surface 154 can match and/or substantially match the contour 145 in the rim 144 of cap 140 such that the electrode ring 125 is securely received within the cap 140, for example. In various embodiments, the contour 145 can be configured such that the electrode ring 125 is substantially flush with the rim 144 of the cap 140 when the electrode ring 125 is positioned in the contour 145, for example. In other embodiments, at least a portion of the electrode ring 124 can extend above and/or below the rim 144 of the cap 140, for example.

Referring still to FIG. 22, the electrode ring 125 can be coupled to an energy source 14 (FIG. 1) by the second conductor 119 and/or the second conductor extension 180. As discussed herein, at least a portion of the second conductor and/or the second conductor extension 180 can extend through the channel 168 in the attachment number and the channel 143 in the cap 140 such that the conductor 119 and second conductor extension 180 electrically coupled the electrode ring 125 to the energy source 14, for example, in the hand piece 16 of the flexible endoscope 12 (FIG. 1). In various embodiments, the second conductor 119 can comprise a conductive wire 182 that extends from a distal portion of the second conductor 119. In various embodiments, the conductive wire 182 can extend from the second conductor 119 to the electrode ring 125. In some embodiments, a groove 184 in a conductor extension 180 can be configured to receive the conductive wire 182. In such embodiments, the electrode ring 125 can be electrically coupled to the energy source 14 (FIG. 1) via the second conductor 119, the wire 182 and the second conductor extension 180, for example.

Referring again to the embodiment illustrated in FIGS. 4 and 5, the electrical ablation device 120 can comprise the electrode probe 124 and the electrode ring 125. Similar to the electrodes 24 a, 24 b, current can flow between the electrode probe 124 and the electrode ring 125 to non-thermal ablate tissue therebetween. In various embodiments, the necrotic zone or the tissue treatment region can correspond to the region in which current flows when at least one of the electrode probe 124 and electrode ring 125 is energized by an energy source 14 (FIG. 1). In various embodiments, the tissue contacting surface 152 of the electrode ring 125 can be positioned against tissue in a tissue treatment region. For example, the tissue contacting surface 152 can be positioned to abut undesirable tissue 48 in the tissue treatment region. Furthermore, the electrode probe 124 can be positioned within the electrode ring 125. In various embodiments, the tissue treatment region can correspond to the region between the contact surface 152 of the electrode ring 125 and the distal end 170 of the electrode probe 125. In such embodiments, current conducted between the electrode probe 124 and the electrode ring 125 can non-thermally ablate tissue therebetween.

In various embodiments, the electrode ring 125 can comprise a cathode and the electrode probe 124 can comprise an anode such that current flows from the electrode probe 124 to the electrode ring 125 when at least one of the electrodes 124, 125 is energized by an energy source 14 (FIG. 1). In other embodiments, the electrode ring 125 can comprise an anode and the electrode probe 124 can comprise an cathode such that current flows from the electrode ring 125 to the electrode probe 124 when at least one of the electrodes 124, 125 is energized by an energy source 14 (FIG. 1). In various embodiments, the electrical ablation device 120 can comprise at least two electrode probes 124 positioned relative to an electrode ring 125, for example. In such embodiments, the electrode ring 125 can comprise a common ground or cathode for the plurality of anode electrode probes 124 positioned therein, for example. Further, current can flow from each electrode probe 124 through the tissue to the electrode ring 125, for example. Further, in various embodiments, the surgeon, operator, or clinician can move the electrode probes 124 relative to the electrode ring 125 to control the tissue treatment region treated by the electrodes 124, 125. In some embodiments, the electrical ablation device 120 can comprise a first and a second energy source. In such embodiments, the first energy source can operably energize a first electrode probe and the second energy source can operably energize a second electrode probe. In various embodiments, the surgeon, operator, or clinician can elect to draw a greater power from the first energy source than the second energy source, for example. In other embodiments, the surgeon, operator, or clinician can elect to draw a greater power from the second energy source than the first energy source, for example.

The configuration of the electrical ablation device 120 relative to tissue can permit the operator, surgeon, or clinician to target undesirable tissue 48 (FIG. 2) in a tissue treatment region. In various embodiments, as described in greater detail herein, the operator, surgeon, or clinician can target tissue in a first necrotic zone 65 a, second necrotic zone 65 b and/or third necrotic zone 65 c (FIG. 2) of the tissue treatment region during a surgical procedure. For example, the geometry of a necrotic zone can be controlled by the relative positions of the electrode probe 124, the electrode ring 125, and tissue. In various embodiments, the position of the distal end 170 of the electrode probe 124 relative to the electrode ring 125 positioned against tissue can determine the necrotic zone 65 a (FIG. 2). As described in greater detail herein, when the tissue contacting surface 152 of the electrode ring 125 is positioned against tissue, the distal end 170 of the electrode probe 124 can translate relative to the interior perimeter 151 of the electrode ring 125. For example, the distal end 170 can translate from a proximal position to a distal position relative to the interior perimeter 151. In some embodiments, the distal end 170 can translate from a retracted position inside of the cap 140 to an extended position outside of or beyond the cap 140. For example, the tissue contacting surface 152 can be positioned against tissue and the distal end 170 of the electrode probe 124 can be moved from the first position within the cap 140 to the second position outside of the cap 140. When the distal end 170 moves to a position outside of the cap 140, the needle tip 172 at the distal end 170 can pierce through tissue in the tissue treatment region.

In various embodiments, a necrotic zone can be controlled by the distance between the distal end 170 of the electrode probe 124 and the contact surface 152 of the electrode ring 125, for example, the distance that the needle tip 172 extends into the tissue. In various embodiments, the needle tip 172 can be flush with or substantially flush with the contact surface 152 such that the necrotic zone comprises a substantially disk-like shape. In other embodiments, as illustrated in the embodiments of FIGS. 23 and 24, the distal end 170 of the electrode probe 124 can be offset from the contact surface 125 such that the necrotic zone comprises a substantially conical shape. For example, referring to FIG. 24, the distal end 170 of the electrode probe 124 can extend a relatively small distance D2 beyond the contact surface 152 of the electrode ring 125 to define a short conical necrotic zone 165 b, for example. In other embodiments, referring to FIG. 23, the distal end 170 of the electrode probe 124 can be extended a larger distance D1 beyond the contact surface 152 of the electrode ring 125 to define a longer conical necrotic zone 165 a, for example.

In various embodiments, the electrical ablation device 120 can be configured to generate a suctioning force. In some embodiments, the electrical ablation device 120 can apply the suctioning force to tissue when the tissue contacting surface 152 of the electrode ring 125 is positioned against tissue. In various embodiments, the cap 140 can direct the suction force to tissue within the inner perimeter 151 of the electrode ring 125. The suctioning force within the cap 140 applied to tissue within the inner perimeter 151 can pull, suck and/or draw tissue into the cap 140, for example. In various embodiments, the magnitude of the suctioning force and/or the amount of tissue drawn into the cap 140 can affect the necrotic zone treated by the electrical ablation device 120.

In various embodiments, similar to electrodes 24 a and 24 b described in greater detail herein, electrode probe 124 and/or the electrode ring 125 can be repositioned during treatment to define additional necrotic zone(s). In some embodiments, the electrical ablation device 120 can treat tissue within four or more necrotic zones during a single treatment. In various embodiments, the electrode ring 125 can be moved to abut a second area of tissue, for example. In such embodiments, the distal end 170 of the electrode probe 124 can be withdrawn into the cap 140 before the electrode ring 125 on the cap 140 is repositioned. Upon repositioning the tissue contacting surface 152 relative to another area of tissue, the distal end 170 of the electrode probe 124 can be re-extended into tissue. In other embodiments, the electrode ring 125 can remain in the same position relative to the tissue, but the distal end 170 of the electrode probe 124 can axially and/or pivotally move. For example, the distal end 170 of the electrode probe 124 can translate axially such that the distal end 170 extends further into the tissue to define a longer conical necrotic zone 165 a (FIG. 23), for example. In other embodiments, the distal end 170 of the electrode probe 124 can be retracted to define a shorter conical necrotic zone 165 b (FIG. 24), for example. In various embodiments, the distal end 170 of the tissue treatment region can be configured to pivot within the cap 140 relative to the electrode ring 125. In such embodiments, the electrode probe 124 can be pivoted to a different position within the necrotic zone, for example.

As described herein, an electrical ablation device, such as electrical ablation device 120, can be used in a variety of surgical procedures to treat a variety of conditions and diseases. An electrical ablation device can be used to transmit pulsed power and/or irreversible electroporation, for example, to treat Barrett's esophagus and polyps. In various embodiments, the electrical ablation device can be secured to an endoscope and can access the undesirable tissue in the tissue treatment region through a small incision or opening. Additional exemplary applications include the treatment of other luminal diseases such as, for example, tuberculosis, ulcerative colitis, ulcers, gastric cancer, and colon tumors. 

What is claimed is:
 1. An apparatus, comprising: a first electrode defining an annular shape having an outer perimeter and an inner perimeter and a tapered tissue contacting surface therebetween; and a second electrode comprising an elongate conductive portion comprising a tapered tip movable relative to the first electrode, wherein the first electrode and the second electrode are configured to conduct electrical current along a conical path through tissue positioned between the first electrode and the second electrode upon energizing at least one of the first electrode or the second electrode.
 2. The apparatus of claim 1, wherein the conical path defined by the first electrode and the second electrode is adjustable.
 3. The apparatus of claim 2, wherein the conical path comprises an adjustable height.
 4. The apparatus of claim 1, wherein the second electrode comprises a proximal end and a distal end, wherein the proximal end is coupled to a conductor, and wherein the distal end is configured to engage tissue.
 5. The apparatus of claim 1, wherein the second electrode is positioned radially within the annular shape.
 6. The apparatus of claim 5, wherein the first electrode and the second electrode are concentric.
 7. The apparatus of claim 1, wherein the second electrode is configured to pivot relative to the first electrode.
 8. The apparatus of claim 1, wherein the second electrode is configured to translate relative to the first electrode.
 9. A system, comprising: an energy source; a first electrode defining an annular shape having an outer perimeter and an inner perimeter and a tapered surface therebetween configured to contact tissue; and a second electrode comprising an elongate conductive portion comprising a tapered tip movable relative to the first electrode, wherein the first electrode and the second electrode are configured to conduct electrical current along a conical path through tissue positioned between the first electrode and the second electrode upon energizing at least one of the first electrode and the second electrode by the energy source.
 10. The system of claim 9, wherein the energy source is a Radio Frequency (RF) energy source.
 11. The system of claim 10, wherein the energy source is a pulsed energy source.
 12. The system of claim 9, wherein the energy source is an irreversible electroporation energy source.
 13. The system of claim 12, wherein the energy source is a pulsed energy source.
 14. The system of claim 9, wherein electrical current conducted along the conical path is selected to non-thermally ablate tissue.
 15. The system of claim 14, wherein the electrical current conducted along the conical path is selected to generate an electric field of approximately 1500 Volts per centimeter.
 16. A method, comprising: positioning a first electrode defining an annular shape having an outer perimeter and an inner perimeter and a tapered tissue contacting surface therebetween relative to tissue; moving a second electrode comprising an elongate conductive portion comprising a tapered tip relative to the first electrode to position the second electrode relative to tissue; and energizing at least one of the first electrode and the second electrode to conduct electrical current along a conical path through tissue.
 17. The method of claim 16, further comprising applying a suctioning force to tissue.
 18. The method of claim 16, wherein positioning the first electrode relative to tissue comprises positioning the first electrode in abutting engagement with tissue.
 19. The method of claim 18, wherein moving the second electrode relative to the first electrode to position the second electrode relative to tissue comprises piercing tissue with a distal end of the second electrode. 